Enclosed arc starting device



March 13, 1951 H. B. DERl 2,545,345

ENCLOSED ARC STARTING DEVICE Filed May 24, 1950 Inventor Hunt/27' B.002/ 7n/77 a/jy Gnu-neg starting an enclosed arc.

' connected.

of the invention having all -a-sa1ed enclosure.

Patented Mar. 13, 1951 2.

ENCLOSED Anc STARTING DEVICE Hubert B. Deri, Rye, N. Y., assignor toGeneral" Precision Laboratory Incorporated, a corporation of New YorkApplication May 24, 1950, Serial No. 163,891

This invention pertains to enclosed arc-lighting devices and moreparticularly to means for starting the arc-discharge in such devices.

This invention is applicable to an'y'type of enclosed are but it isespecially useful when applied to that'type of enclosed arc lampforproducing visible light in which light, isproduced principally at thesurface of the'cathode electrode. Such an enclosed .arc'is described inthe copending patent application Serial No..

83,129 of Hubert B. Deri, filed March 24, 1949. I Enclosed arcs areordinarily started by the "application of an elevated voltagesuperimposed upon the arc supply circuit so as to be effective acrossthe arc electrodes. This elevated voltage fmay be either alternating atlow or high frequencies, rectified or pulsed direct voltage, or

a momentary inductive surge caused by breaking the current through aninductor. In each of these methods of starting, equipment is requiredwhich is bulky and expensive, so that a need has long existed for abetter and cheaper method'of starting the arc discharge.

The instant invention provides means for moving one of the electrodeswithin the arc enclosure and without breaking the hermetic seal thereof,to touch the electrodes together momentarily to start the current flow.Then when the electrodes are separated the arc is drawn between them.Means are also provided for 11 Claims. (o1. tie-"152);-

metal-to'fglass seal, indicated at H.

Referring now to Fig. 1, an embodiment of the invention chosen forpurposes of illustrating the invention comprises a gas-tight envelopehaving a metal cylinder ll closed and sealed at one end by a transparentglass disc I2. To the other end of the metal cylinder I! is sealed oneend of a flexible metallic bellows l3, the other 'end of the bellowsbeing sealed to' a metal disc 14. A metal tube [5; drawn to'an enlargedscale for clarity, extends through a central. hole in the disc Hi; thedisc and tube It being sealed together mechanically and electricallyinsulated each-fro the other, by the interposition ofila Themetal tube16 constitutes part made cathode structure. Thecathode is, per se,comprises a plug of metallic oxides serving as automatically startingthe arc, if for any reason 7 the arc should be extinguished. Therefore,one purpose 'of this invention is to provide a simple and inexpensivemeans for Another purpose is to provide an improved ent closed arc lampstructure in which the t'wo-elecwithout affecting the hermetic'seal Afurther purpose is to provide improved electrodes are readily movablerelative to eachl'o ther :t'rically operated mechanical starting meansfor an enclosed arc.

A still further purpose is to provide an improved electrical startingmeans for ane'nclosed arc lamp that automatically restarts the lamp ifit becomes extinguished while power remains Abetter understanding of theinvention can Figure 2 is a cross section of a modified form movingparts Within 'a light emitter. e 'is fiush with the end IQ of the tube[6. A hole The exposed end 28 of this plug 15 in the tube l6insures'equal ization of gas "pressure on both ends of the plug I8. Theother end 2| of the tube I6, opposite to the cathode end, is utilized asthe tubulation for exhausting the envelope and filling it with an inertgas, after which it is pinched off and sealed. A ceramic disc 22 isfixed in the cylinder H to serve as-a guide for the tube [6, fixing itagainst transverse movement while permitting axial movement. Holes 20 inthe disc 22 insure equalization of gas pressure on the two sides of thedisc. A stop ring 23 is fixed to the tube l6; and a" compression spring24 is provided inside the bellows l3, with the respective ends of thespring {such that normally the cathode tube I6 is forced serve as theanode. "ably made of tungsten'or molybdenum. It has 1 an aperture 21preferably o'fcohi'cal 'shape;"so

-to the left until the'stop ring 23 abuts the ceramic disc guide 22.

-' The gas with which the envelope is filledmay be of any desired inertkind, for example argon or helium, and at any; desired pressure" whichwill maintain an arc discharge without appreciably combining with theelectrode materials during operation of the arc. In this embodiment thepressure is approximately oneatmosphere.

- A metallic disc 26 is fixed in the cylinder I l' to The disc anode 26is prefer- [that light emitted by". the emitting surface 28 of theemitter-plug [8 can radiate out of the arc lamp through. the transparentdisc window [2. The inner edge 29 of the aperture 2'! is in line itswith the --inner edge 3l .of the tube. l6, so. that of magneticallypermeable material, or at least.

so much of member 33 as encloses the solenoid 32.

A brass member 38 is press-fitted over the tube I6 and is provided witha screw-threaded .stud

39 which engages a threaded bore "ma magthat constinetically permeableextension 4| tutes an armature for the solenoid 32. The solenoid ismounted on anonpermeable cylinder "42 to allow the magnetic effect ofthe solenoid -to be exerted upon the armature 4|. The material of thelining 42 is chosen to be electrically *nonconductive to obviate thepossibility of short- :circuiting the electrodes during any sidemotionof the armature 4|.

A direct current supply of electrical power-is applied at terminals 43and 44, a stabilizing impedance being interposed in series with eitherone of the supply terminals as indicated by the TIesistor'46"c0nnectedto the negative terminal 43. From the other end of the resistor 46connection is made to a terminal--41 on the frame v33 of the arc-lightdevice, the terminal 41 being insulated from the casing 33 by a pad ofinsulating material 48. This terminal 4'| is electrically connected by aconductor 49 extending through the opening 45 to the cathode tube Hi.The

positive supply terminal 1-44 is connected to a zterminal 5|electrically connected to the metallic envelope H of the enclosed arc,which is in thermal and electrical contact with'the anode disc 26. Thetwo terminal conductors 52 and 53 of the solenoid 32 are connected,respectively, to

the two terminals 41 and 5|, putting the solenoid in shunt with theelectrodes l8 and 26. v

Before the enclosed arc is put into operation the relative positions ofthe anode 26 and cathode l8 are as shown in Fig. 1, with the cathodestop 23 pressed against the ceramic guide 22 by the :spring 24, and withthe cathode and anode separated. The cathoderand anode are thereforeinsulated from direct contact with each other but as they are shunted bythe solenoid 32. a current path exists from the positive-terminal -44 toterminal 5|, through conductor 53 through the solenoid 32 andconductor52 to terminal 41,-

. and thence through resistor ,46 tothenegative supply terminal 43.When, therefore, a suitable potential is applied to the terminals 43 and44 the solenoid 32 is energized and moves the plunger .4| to the rightto a position nearer the'center of the solenoid. Movement of theiplunger4| moves the tube l3 against the force of the spring 24 and toward theanode 26, so that the end IQ of the tube It is pressed against the metalanode 26 and makes electrical contact therewith. With electrodes incontact the solenoid 32 is short- -cir cuited and thereby de-energized,permitting the spring 24 to restore the cathode l6 to its formerposition with its stop 23 pressed against the guide 22. Duringthisaction, as the cathode tube end --.|9 leaves the anode lip 23, anarc is drawn between these two parts. Experienceshowsthat- The remainderof member 33 may be made of insulating material, if desired. The ends 35and 3'! also are permeable for the same reason."

4 the cathodic termination of the are, that is, the point on the cathodeat which the arc terminates, quickly migrates to the center of theemitterplug |8 of the cathode. It will readily occur to those skilled inthe art that instead of the shunt solenoid, a properly designed seriessolenoid could be substituted. In the latter event, it would benecessary to arrange the springso that the cathode I3 is normally urgedtoward the anode when no current is flowing. Then when current wasflowing the solenoid would retract the cathode to start the arc.

After the arc starts, its impedance being substantially less than thatof the solenoid 32, the

short-circuit of the solenoid is effectively continued, so that thesolenoid 32 remains de-energized as long as the arc is maintained. If,however, the arc should be extinguished in any manner, while theelectrical power supply remains connected to the device, as for instanceby a transient pulse of opposing polarity superimposed upon the supplypower, the solenoid 32 is then immediately reenergized-and the abovedescribed starting action automatically takes place again, restartingthe are.

It is obvious that the arc can be started man- -ually by pressing; theprojecting end 54 of the armature of plunger 4| until the anode 23 andcathode |8 make contact with each other, then releasing the armature,Whichis-returned to its normal operating position by the spring 24,drawing and starting the arc as before described. In 'such manualoperation the solenoid 32 is-not necessary and may be omittedzfrom thedevice, .and the automatic-restarting will of coursenot occur; Suchmanual operation can of course be effected not only by pressing with thehand against the plunger 4| but as well by moving the a; second metalcylinder 59, an end disc 6!, and a-cylindrical electrical terminal 52'sealed to the conical aperture 65. Behind this aperture is the cathodestructure consisting of a cylindrical bar 66 having a recess 6'! in theforward end filled with a plug of emitting material the outer end ofwhich is flush with the plane of the end'68. This end is so positionedthat upon movement of-the icathode to the anode themetal rim of the'end-58 makes metallic contact with the metal anode disc 64. The bar 66 isguided by two guide discs 69 and 1|, made of insulating material,preferably, ceramic material. Both discs have perforations 12 toequalize the gas pressure on the op-- posite sides of the-discs. Amagnetically permeable armature disc 16 is fixed to the end 14 ofthe.,-ba.r 66by means of a suitable screw 15 whichalso secures one end of atension spring 11 to the bar :66. The other end of the spring 1! isseouredby I means of a screw 80 to the electrical terminal 62.

The spring 11 is preferably made of a material I having good electricalconducting properties, such as Phosphor bronze, because it must carrythe current through the arc. The barfifi has a-stopo What is claimedis: 1. An enclosed arc c'ollar 18 which normally is pressed against the-guide disc 69 by the tension of the spring 11, holding the anode andcathode apart at aspecific distance.

A coil 19 is positionedupon the cylinder 5.! and an annular flat ring 82of magnetic material cooperates with the permeable cylinders 8| and 83to provide a magnetic path of'increased'permeability. The magnetic pathis open on the side adjacent the insulating'and nonmagnetic ring 58 toincrease the magnetic flux through the armature 1 6.

Electrical power is applied from direct current terminals 84 and 96through a series stabilizing resistor 8'! to an anode terminal 88 and aoath ode terminal 89, respectively, so that the power to the arc issupplied from the anode terminal 88 "through the annular ilat ring 82and thecylin'der 51 to the anode disc S t, and from the: cathodeterminal 89 through electrical terminal 62 'f'and spring l1 to thecathode bar 66 and the emitting material in the'recess 61. The terminalconductors 9i and 32 are connected to the'terminals 7 =88 and 89 so thatthe coil 19 is in shunt with the arc electrodes.

' Upon application of electrical power to the ter:

'minalsBA and 86 the coil 19 is energized, attract ing the disc armaturel6 and forcing the cathode bar 66 into contact with the anode 64 againstthe tension of spring Tl. Upon contact, the coil is 'deenergized,

the spring'retracts the cathode bar, and an arc is drawn, the lowimpedance of the arcin shunt with the coil preventing reactuation"thereof as long as the arc is maintained. If the ,arc should go outwhile power remains on, the

starting action is automatically repeated to re k start the arc. Y

. The action of this embodiment is thus similar 'to that of theembodiment of Fig. 1, a principal difference being that in Fig. 2 themagnetic arma ture is within the seaed envelope.

It is obvious that numerous other combinations may be made of solenoidsof various types with various sealing arrangements that will beequivalents of the described preferred embodiments. As an example, asimple flexible diaphragm may be substituted for the two embodimentsshown. Also, it wi l be readily apparent that either electrode may bemovable.

lamp comprising, a gastight metallic tubular envelope enclosing an-inertgas atmosphere and having a transparent window sealed in one end of saidtubular envelope, a oath ;ode assembly insulatingly sealed to the otherend .of said envelope and comprising a metallic tubular support memberhaving a recess facing said window and having a light emissive materialfilling at least the outer end of said recess, said elongated supportmember being supported for longitudinal movement within said envelope, adisc shaped metallic anode positioned between said cathode and saidwindow and having its periphery in intimate electrical engagement withthe interior surface of said metallic envelope, said disc shaped anodehaving an aperture in the center thereof for transmission of lighttherethrough from said cathode, the size of said ,,aperture beingsubstantially the same as that Q'f said recess in the elongated supportmember of said cathode assembly, and means for moving said cathodeassembly toward said anode for momentary contact to strike an arebetween said elongated support member and said anode.

2. An enclosed arc lamp comprising, a gastight metallic tubular envelopeenclosing an inert gas atmosphere, a disc anode fixed in electricalcontact within the surface of said envelope and positioned transverselyof the axis of said cylinder, a cathode assembly insulatingly sealed tosaid envelope and comprising a metallic elongated support member havinga recess in the end thereof which is within said envelope, said recesshaving light emissive material filling at least the outer trodes formoving said elongated support member against said anode for momentarycontact to strike an arc.

4. In an enclosed arc lamp, a gastight metallic tubular envelopeenclosing an inert gas atmosphere and having a transparent window sealedin one end thereof, a disc anode fixed in electrical contact with saidenvelope and positioned within said envelope adjacent said window, a

cathode assembly insulatingly mounted within said envelope for movementaxiallyof said en- -velope, said cathode assembly comprising a metallicelongated tubular member having a recess in the end thereof facing saidwindow, said recess having light emissive material filling at least athe energization of said electrodes for moving said elongated supportmember toward said anode for a momentary contact to initiate the arcdischarge. I

5. An enclosed arc lamp as defined in claim 4 in which said means formoving said elongated member toward said anode is responsive to theinitiation of the arc to permit said resilient means to thereafter movesaid elongated support member of said cathode assembly to a positionspaced from said anode to maintain the continuation of said arc.

6. In an enclosed arc lamp, a gastight tubular envelope enclosing aninert gas atmosphere and having a transparentwindow sealed in an endthereof, a cathode assembly insulatingly supported within said envelopeand mounted for movement axially of said envelope, said cathode assemblycomprising a metallic elongated tubular member having a recess at theend thereof facing said window, said recess having light emissivematerial therein, a disc shaped metallic anode positioned between theend of said elongated member having said light emissive material andsaid window, said metallic anode having its periphery in electricalengagement with the interior surface of said metallic envelope andhaving a central aperture therein for transmission of light therethroughfrom the light emissive material in said elongated tubular memher, amagnetic armature on the other end oi said elongated tubular membermeans magnetically associated with said armature to move said elongatedtubular member into engagement with said anode to initiate the are.

7. In a combination with the enclosed arc lamp defined in claim. 6,resilient means for normally holding the recessed end of said tubularmember at a position spaced from said anode member, -means for applyingan energizing potential between said cathode and said anode, and anelectromagnet connected in parallel with the electrodes for magneticassociation with said armature for moving said elongated member towardsaid anode for momentary contact with the latter to strike an arcbetween the electrodes.

.' 8. In an enclosed arc lamp, a gastight metallic tubular envelopeenclosing an inert gas atmosphere and having a transparent window sealedin an end thereof, a cathode assembly insulatingly sealed in the otherend of said envelope and comprising a metallic elongated support memberhaving a recess at the end facingsaid window said recess having lightemissive material filling at least part of said recess said elongatedsupport "member being supported for longitudinal movement within saidenvelope, a disc-shaped metallic anode positioned between said cathodeand said window and having its periphery in intimate electricalengagement with the interior surface of said metallic envelope, anaperture in said anode for transmission of light therethrough from saidcathode, an electrical solenoid, an armature op.- erably associatedtherewith fixed to said elongated support member of said cathodeassembly for moving the latter into contact with said anode, andelectrical connections connecting said solenoid and said anode andcathode in parallel. 9. In an enclosed arm lamp a gastight metallictubular envelope enclosing an inert gas atmosphere, said envelope havinga transparent window sealed in one end thereof, an expansive metallicbellows sealed to the opposite end of said envelope, a cathode assemblyinsulatingly sealed to the other end of said metallic bellows,

said cathode assembly comprising a metallic elongated tubular membermounted for movement axially of said envelope and having a recess at theend thereof facing said window, said recess having a light emissivematerial filling at least a portion thereof, a disc shaped metallicanode positioned between the end of said tubular member andsaid windowand adjacent said window, said anode having its periphery in intimatethermal and electrical engagement with the interior surface of saidenvelope, a central aperture in said anode for transmission of lighttherethrough from said cathode, a metallic ar mature fixed to the end ofsaid elongated tubular member opposite to the end containing saidrecess, a solenoid surrounding said armature for coaction therewith andresilient means for normally positioning the recessed end of saidtubular member away from said anode and in opposition to the action ofsaid solenoid 10. In an enclosed lamp, a metallic tubular envelopehaving a transparent wmdow sealed in one end'thereof and a metallicsupport insulatingly sealed in the other end thereof, a cathodeassembly-axiall supported for limited longitudinal movement within saidmetallic tubular envelope comprising a metallic elongated support memberhaving a recess at one end thereof and having a light emissive materialfilling at least part of said recess, a disc-shaped metallic anodepositioned between said cathode and said window and having'its peripheryin intimate thermal and electrical engagement with the interior surfaceof said metallic envelope, an aperture in said anode for transmission oflight from said cathode therethrough, a filling of inert gas in saidenvelope, a tension spring connecting the'end of said metallic elongatedsupport member opposite said recess to said metallic support within saidenvelope, a magnetically permeable armature affixed to said metallicelongated support member. and a solenoid positioned to coact with saidarmature to draw said cathode assembly intocontact with said anodeagainst the re,- tractile force of said tension spring. I

11. An enclosed arm lamp as defined in claim 10 including means forapplying an energizing potential across said cathode and anode and meansconnecting said solenoid in parallel with said electrodes whereby uponinitial energization of said solenoid and said electrodes said cathodetubular member will be brought into momentary contact with said anodemember to initiate an arc discharge, the contacting of the electrodesand the subsequent arc discharge serv- HUBERT B. DERI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 274,997 Van Ch-oate Apr. 3, 1883639,786 Spies Dec. 26,1899

